Abstract

In this study, a label-free capacitive aptasensor was developed based on capturing of human epidermal growth factor receptor 2 (HER2) protein by anti-HER2 ssDNA aptamers functionalized on interdigitated microelectrodes of capacitor as bio-recognition elements. The aptasensor response was measured by non-Faradaic Impedance Spectroscopy (nFIS) method. Capacitance signal specific to target HER2 protein is based on changes occurred due to charge distribution upon interaction of aptamer-protein molecules against to the applied AC frequency (50-350 MHz). HER2 protein in spiked human serum was successfully detected through concentration dependent changes in impedance/capacitance values as a result of the formation of aptamer-HER2 protein complex (0.2-2 ng mL(-1) of HER2) on capacitor microelectrodes. The label-free capacitive aptasensing is a versatile and promising approach for early detection of cancer biomarkers in dilute human serum and the method potentially be extended to a wide variety of diseases biomarkers.